Mum catches duo filming teen girls in locker room

Who planted the camera? The answer is rather shocking...

Mia Walker is on her school swim team. Before practice, she changes into her swimsuit at a leisure centre locker room.

She had no idea that for four months, a woman was secretly videotaping her and the other youngsters getting undressed.

The camera was discovered by pure accident by Mia's mother, Christina. Video obtained by Inside Edition shows Christina noticing the glare of a camera lens coming from one of the lockers. Who planted the camera? It's hard to believe, but it was another mum. Find out more on the story in the video above.